Carpal tunnel syndrome is a clinical condition brought upon by a compressed or pinched median nerve at the wrist. Usual symptoms of this condition are numbness, tingling and pain in the hand, fingers and arm. This occurs when pressure builds up within the tunnel for various reasons, such as swelling of the lining tissue of the tendons, fracture, dislocation or arthritis of the wrist, all of which compresses the median nerve which causes carpal tunnel syndrome. The carpal tunnel is a narrow channel through which nine flexor tendons and the median nerve pass. The dorsal floor (base) of the tunnel is formed by a concave arch of carpal bones covered by intrinsic and extrinsic palmar wrist ligaments. The roof of the tunnel is formed by a transverse carpal ligament which is about 2-3 mm thick, 3-4 cm wide and approximately 3-4 cm long. This ligament is rigid and does not stretch and the treatment of this condition is usually and initially conservative, i.e., rest, splint, and medication.
When the symptoms are severe and constant and if the patient fails to respond to the aforementioned conservative treatment, surgical intervention is necessary. The surgery involves the release (splitting) of the transverse carpal ligament in the vertical (up and down or along the longitudinal axis of the hand) direction which in turn decompresses the tunnel. To achieve release of the transverse carpal ligament, an incision is made in the skin on the palmar aspect of the wrist, or can be made in the vertical direction (i.e., longitudinal) on the hand, or some modification of a vertical incision can be made to expose the ligament, followed by cutting of the ligament as mentioned above.
When the incision is made in the vertical or longitudinal direction on the palmar aspect of the hand, the resulting complete exposure of the transverse carpal ligament ensures easy splitting or cutting of the ligament with minimal risk of damaging the nerves, blood vessels, or obtaining incomplete release of the ligament. However, when the incision heals, there is extensive scar tissue which is both unsightly and painful and may impair full recovery of hand function. When the incision is made transversely along the skin crease of the wrist, there are advantages such as rapid healing, shorter recovery time, and excellent scar formation following surgery. However, there are also disadvantages resulting from poor exposure of the ligament during the surgical procedure which can then, during cutting, increase the risk of damaging the nerves, blood vessels, while possibly obtaining incomplete release of the ligament.
The trend in this surgery is to search for a means of achieving better exposure of the ligament through a small transverse incision and, as such, a procedure known as endoscopic release of the carpal tunnel is becoming popular. In this approach, there is utilized a scope which is a rigid tube having a lens at one end through which view of the surgical field is being transmitted into the TV monitor for surgeons observation, followed by cutting of the carpal ligament with a special knife contained in the tube. However, this approach does not provide adequate exposure of the median nerve which in turn increases the risk of potential damage to the nerve or its branches. Also, additional training of the surgeon is necessary to perform the endoscopic release. The procedure itself is time consuming and, furthermore, the setup for the endoscopic carpal tunnel approach is quite expensive. Finally, the use of a special kit (i.e., special knife and dissector, etc.) is required for each patient which is therefore costly.
It is accordingly one object of the present invention to obtain complete release of the carpal ligament while avoiding damage to the median nerve or its branches.
Another object is to completely release the carpal tunnel ligament through a small transverse incision and without either a vertical incision or utilization of an endoscopic approach.
Another object is to provide surgical equipment and method of use without requiring substantial additional training of the surgeon and without requiring expensive special equipment.
Still another object is to obtain complete release of the carpal ligament through a small transverse incision using equipment which does not require elaborate and time consuming setup.